1. Field of the Invention
The present invention is in the field of industrial speed reduction drives and relates more specifically to a compact and cost efficient roller driven rotary speed reduction drive.
2. Prior Art
Speed reducers for industrial use conventionally comprise chain and sprocket drives, belt and pulley drives, and gear drives. Each of the noted types of drives has limitations which are well known to skilled workers in the art.
By way of example, where large speed reductions are required. e.g. in the range of 10:1 or more, none of the known drives has proven commercially satisfactory in general application without the use of three or more driven shafts. More particularly, in belt and pulley drives using two pulleys, a 3:1 or 4:1 ratio is about the maximum generally expected, whereby the achievement of ratios in the 10 to 12 to one or more range mandates two successive stages of speed reduction with the attendant increased expense of providing three or more shafts and associated bearings, etc.
Similar drawbacks inhere in the use of high ratio reduction sprocket drives.
Geared speed reducers are similarly limited in the amount of reduction which may be achieved in a single stage, since, where the sizes of the meshing gears vary widely, driving force is applied through a relatively small meshing-tooth area. Also, geared speed reducers are expensive, due to the inherent machining and finishing operations required in the fabrication of gears, the necessity for providing lubricant containing housings, etc.
While it is known to provide geared planetary speed reduction devices, the complexity of these units render such units suitable for only the most specialized installations where costs are not a significant factor.